1. Field of the Invention
The present invention relates to a light emitting device package and a manufacturing method thereof allowing for improved light uniformity by forming a wavelength conversion layer in an opening of a substrate.
2. Description of the Related Art
Recently, as the brightness of a light emitting device such as a light emitting diode (LED) has increased, such a light emitting device has been used as a light source for a display device, alighting apparatus or a car. Alight emitting device is able to emit white light by using phosphors or by combining light of various colors. In order to use an LED for such a purpose, the device should be low in operational voltage and high in light emission efficiency and brightness.
The most general method for the implementation of a white LED converts light wavelengths by using a blue LED and a yellow phosphor and combines blue light and yellow light to thereby emit white light. In this method, the efficiency of phosphors may greatly affect the emission of white light.
A general structure of a white LED using a phosphor layer is manufactured as a package. An LED is die-bonded to a lead frame formed of a conductive metal using a bonding resin and a filling material formed of a composite resin such as silicon resin, epoxy resin or the like is molded around the upper part of the LED. In order to allow the LED to emit white light, a phosphor powder is mixed with the filling material and the mixture is molded in the lead frame package having the LED bonded thereto.
Such a white LED package emits white light in a manner such that a portion of the blue light emitted from the blue LED is transmitted while the remainder thereof reaches the phosphors included in the filling material, causing yellow light through the excitation of the phosphors to be emitted, and thus blue light and yellow light are combined to thereby emit white light. In this case, a difference in the paths of light beams is caused when light reaches the outer surface of the package, and accordingly, it may be difficult to achieve light uniformity. In addition, due to the non-uniformity of the phosphors included in the filling material, color reproduction characteristics may be reduced.